Abrasive device



Oct. 11, 1938`. Y Y' J. 1 BALLAsH 2,133,009

ABRAs'IvE DEVICE v Filed. Nov. 16,.1936

ATTORNEY 5 Patented Oct.

UNITED STATES PATENT OFFICE,

4 claims. (ci. si-zos) This invention relates to an abrasive device of the type comprising an annular chuck and a segmental grinding ring held therein. The invention has reference particularly to improved means for clamping and holding the segments yin place in the chuck.

In an abrasive device or grinding wheel of the type herein contemplated, the segments are clamped in place by an externally tapered clamping ring which brings the contiguous edges ofthe segments into tight clamping engagement with one another and thereby necessarily contracts the segmental ring. The foregoing construction in itself provides an effective clamping means, but, according yto the provisions of the present invention, this means is augmented by an internal support for the upper ends of the segments in the form of an internal flange or shoulder, having a slight clearance between it,

and the inside ofthe wheel. The clearance between the internal segment support and the wheel allows the adjacent edges of the segments to be brought inv tight clamping engagement with each other in the normal manner but prevents or limits the spreading or aring of the outer ends of the segmentsr undery the action of centrifugal force. This clearance between the internal supports for the segments and the wheel proper lls up with'abrasive material during operationof the device which tends to decrease the clearance and better support the segments.

The object of the invention is, therefore, to provide an abrasive device or grinding wheel of the type above mentioned'wherein an improved, novel, and exceedingly effective clamping vor holding action on the segments is obtained.

'I'he invention may be further briefly summarized as consisting in certain novel details of construction and combinations and arrangements of parts which will be described in the specification and set forth in the appended claims.

In the accompanying `sheet of drawings showing the preferred embodiment of the invention and certain slight modifications,

Fig. 1 is a side elevation of an abrasive device embodying the present invention, comprising a chuck and a segmental ring type abrasive member;

Fig. 2 is a bottom view of the abrasive device shown in Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a section similar to Fig. 3 but showing a modified construction;

Fig. 5 is 'a fragmentary perspective view of the chuck shown in Figs. 1, 2, and 3, showing a different form of abrasive member secured therein; and

Fig. 6 is a fragmentary view similar to Fig. 2, showing a still further form of abrasive member.

The present invention is especially applicable to surface grinders of the type comprising a vertical spindle to the lower end of which is secured an abrasive device including a chuck or holder vand an abrasive member, in this instance a segmental abrasive ring, secured in the chuck and projecting from the lower side thereof.

Referring now to the drawing, I0 represents the body of the chuck which is designed to be secured to the lower end of the rotating spindle of the grinder in this instance by bolts adapted to engage in tappet holes II .which are provided in an elevated part of the chuck body somewhat near its inner periphery, the chuck body being generally in the form of an annulus the vcrosssection of which is indicated in Fig. 3. Additionally, the abrasive device includes an abrasive member in the form of a segmental ring wheel or annulus I2 the upper part of which extends into the lower side of the chuck and is clamped therein. The adjacent segments are in Aengagement ywith each other at least for a portion of their depth, preferably the full depth, and their edges are preferably interlocked by a tongue and groove construction shown at I2b in Figs. 1 and 2, wherein the segments are designated I2a. 'I'hat is to say, each segment has on one upright edge a groove and on its opposite edge a tongue, and when the segments are assembled in the chuck and are clamped in place, the tongue of one segment engages the base of the groove of theV adjacent segment, but preferably inwardly and outwardlyof the engaging portions clearances are provided between the segments which are therefore generally ofthe construction constituting the subject matter of '2 aisaoos anges I3 and It 'mayY both be integral with the chuck'body, as shown in Fig. 3, but either or both may be separate members attached to the body of the chuck. Generally, the outer flange I4 is integral, but in some instances the inner ange is a separate member secured vto Y the chuck body, as shown at I 3a in Fig. 4, which shows the inner flange formed as a part of an annular angle member I5 Vsecured. to the -chuck body by screwsor bolts I 6. The constructions .shown in Figs. 3 and 4 are otherwise similar.

The surface of the ange I8 or I 8a adjacent the abrasive wheel is cylindrical and a small l clearance is provided between the same and the" inside diameter oi' the abrasive wheel. 'Ihe innerY surface of the outer iiange- I4 is tapered to accommodate an outer tapered split clamping ring I l, the inner cylindrical surface of the clamping ring I1 engaging the outer arcuate surfaces of the segments. The split clamping ring I'Ils designed to be drawn inwardly to clamp the segments in place byV bolts I8 which have threaded engagement with the clamping ringV and pass through openings in the chuck body, the openings being large enough to provide clearance for the shanks of the bolts as they move laterally inwardly slightly when the bolts are tightened, i. e., during the clamping operation.

In assembly.A the segmental abrasive ring Il! is placed in the channel of the chuck between the inner ange I3 (or i3d) and the outer split clamping ring I l. I 'I'hen the clamp Il is drawn j inward by turning the bolts I8, contracting the segmental ring I2 and causing the edges of the segments to be drawn into tight clamping engagement. I'his in itself causes a clamping or holding action in the chuck'body, but I find that a still more eiective holding action .is obtainedby the lprovision of the inner iiange or wall I3 or I3a. The annular surface of the inner flange is so positioned with reference to the segmental abrasive ring I2 (taking into consideration the diameter of the inner surface of the abrasive ring I2 at the time the segments are .brought into tight clamping engagement when the wheel is being contracted by the split clamping ring I1) that it does not interfere with the normal clamping of the segments, which when brought intoclamping engagement with one another by the contraction of the ring have a slight;v clearance I9 of about ab" with the inner annular walll I3 or I3a. Particularly does the inner wall prevent the lower orworking ends of the segments from spreading or fanning later-y ally outwardly under the action of centrifugal force and all danger of disruption or explosion of the wheel in operation is prevented. 'Ihe accumulation of abrasive material worn from `the wheel during operation in the clearance I9 has a tendency to decrease the clearance between the inner wall I3 or I3a and the inside ofthe abrasive wheel. 'Ihis decreases the clearance, more securely clamps the segments in the` chuck, and assists in preventing the outer ends of thesegments from arlng laterally outward during operation.

The clearance between the grinding -ring and the internal flange of the chuck should be kept as smallas practical without having the internal ange interfere with the initial'clamping of the segments and in no event should it greatly exceed 95".' If the groovek between the grinding ring and the internal angeof the chuck is too each other so that the clampingeect produced by the contraction of the ring will obtained as before.

In Fig. v6 I haveshown a segmental abrasive wheel wherein the segments, here designated Ie, have nat engaging edges |21'. As here illustrated, the segments engage on nonradial lines, but the engagement may be on radial lines if desired. This figure also shows the segments abutting tight against one another but it is to be understood that a slight clearance therebetween might be provided at the lower ends of the segments so long as there is sumcient bearing at the upper ends of the segments for clamping purposes. v

While I have illustrated certain embodiments of the invention, it will be apparent. that other changes may be made in details of the segments and of the chuck, vand. I therefore aim in my claims to cover all modications which do not involve a departure from the spirit and scope of my invention.

Having thus described my invention, I claim:

l. An abrasive device comprising a chuck and a segmental grinding ring, the segments having edge portions in engagement with one another, the chuck Vhaving means located exteriorly of the segments for contracting the ring and thus forcing the edges of the segments in tight clamping'engagement with one another, and an inner wall spaced from said grinding ring but adjacent thereto forming a narrow groove not greater clamping engagementv between the engaging edges of the segments, and an inner wall adjacent said abrasive wheel but having a slight clearance therewith forming a groove about is" wide adapted to collect particles worn'from the wheel and prevent tilting of said segments about the clamping means' and spreading or daring of the wheel during operation.y

j 3. An abrasivev device comprising an annular chuck having a channel formed on one side thereof including two opposed surfaces the inner being cylindrical and the outer being tapered, a segmental abrasive ring composed of segments having their adjacentedges in contact with one another extending into the channel in spaced relation to the inner cylindrical surface, and a split clamping ring located in the channel exteriorly of the segments and in engagement therewith and having a tapered surface in engement with the tapered surface of the chuck channel, and means for adjusting the clamping ring, said inner cylindrical wall being adjacent the inside of the abrasive ring but slightly spaced therefrom forming a groove about 5k" wide withthe chuck is to be used and adapted to form therewith a narrow deep groove not greater than about 1% wide within which particles worn from the wheel are adapted to accumulate, and the outer wall having a tapered surface, a split clamping ring having a tapered surface engageable with the tapered surface of vthe chuck, and bolts engaging the chuck and the clamping ring for adiusting the latter.

JOSEPH L. BALLASH. 

